6640247 has 4 divisors (see below), whose sum is σ = 6650040. Its totient is φ = 6630456.

The previous prime is 6640241. The next prime is 6640289. The reversal of 6640247 is 7420466.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 6640247 - 2¹⁰ = 6639223 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6640241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3797 + ... + 5262.

It is an arithmetic number, because the mean of its divisors is an integer number (1662510).

Almost surely, 2^6640247 is an apocalyptic number.

6640247 is a deficient number, since it is larger than the sum of its proper divisors (9793).

6640247 is an equidigital number, since it uses as much as digits as its factorization.

6640247 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9792.

The product of its (nonzero) digits is 8064, while the sum is 29.

The square root of 6640247 is about 2576.8676721943. The cubic root of 6640247 is about 187.9582580482.

The spelling of 6640247 in words is "six million, six hundred forty thousand, two hundred forty-seven".